This invention relates to a primer mix for a percussion primer. More particularly, the substantially lead free primer mix contains calcium silicide and dinol. The primer mix has sufficient sensitivity for use in both Boxer and Berdan primer systems.
For approximately the last fifty years, the primary explosive used in small arms primer compositions has been lead styphnate. The lead styphnate is combined with oxidizing and reducing agents, sensitizers and other fuels. Typical additions to lead styphnate include tetracene, aluminum, antimony sulfide, calcium silicate, lead peroxide, boron, pyrophoric metals and barium nitrate. Variations in the ingredients and their relative amounts result in chemical systems which possess sensitivity and propellant ignition properties tailored to specific requirements. These priming compositions are, and for the most part, still in current use in small arms primers.
However, concerns over environmental hazards and the potential effects on individual health, primarily in indoor shooting ranges, has lead to concerns with the primer exhaust. The lead styphnate based primers exhaust toxic oxides of lead, and typically also barium and antimony oxides. Extensive research has been done to find a replacement primer which (1) does not produce toxic exhaust products; (2) has a consistent ignition pressure and velocity; (3) and has sufficient sensitivity for use in both Boxer and Berdan priming systems.
Non,toxic primer compositions are disclosed in U.S. Pat. Nos. 4,963,201 to Bjerke et al and in 5,167,736 to Mei and Pickett, both of which are incorporated by reference in their entireties herein.
The Bjerke et al patent discloses a non-toxic primer mix containing dinol, tetracene, a nitrate ester fuel and strontium nitrate. The exhaust product from ignition of this mix does not contain lead, barium or antimony oxides. The exhaust product does contain strontium oxide slag. The sensitivity is less than that of a lead styphnate based primer. While suitable for use in Berdan primers, the sensitivity is marginal for Boxer primers.
The Boxer primers have a self contained anvil which allows the primer to be sold as a component and the pistol user can reload shells. The capability to reuse shells makes priming mixes having sufficient sensitivity for use in Boxer primers desirable in both military and commercial applications.
The Mei and Pickett patent discloses a non-toxic primer mix for use in both Boxer and Berdan percussion primers. The mix contains dinol and boron. Calcium silicide is disclosed as useful as an abrasive sensitizer and as a reducing agent.
While these non-toxic priming mixes are suitable, there exists a need for other non-toxic priming mixes which have sufficient sensitivity for Boxer primer systems.